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(No Model.)

. S. ANDREWS & A. K. WARREN.

RHEOSTAT.

Patented Dec. 22 1891.

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UNITED STATES PATENT OFFICE.

TVILLIAM S. ANDRElVS AND ALDRED K. \VARREN, OF NE\V YORK, N. Y.,ASSIGNORS TO THE EDISON GENERAL ELECTRIC COMPANY, OF SAME PLACE.

RH EOSTAT.

SPECIFICATION forming part of Letters Patent No. 465,512, dated December22, 1891.

Application filed August 25, 1891. Serial No. 03,667. (N0 model.)

To ctZZ whom it may concern;

Be it known that we, WILLIAM S. A NDRE we, a citizen of the UnitedStates, and ALDRED K. \VARREN, a subject of the Queen of Great Britain,both residing at New York city, in the county and State of New York,have invented a certain new and useful 1m provement in Rheostats forFan-Motors, of which the following is a specification.

The present invention relates to means for controlling the speed ofelectric motors used to drive ventilating-fans; and the inventionconsists in supporting a resistance-conductor on the fan-guard, and incertain combinations of devices hereinafter fully described and claimed.

In the accompanying drawings, Figure 1 is a face view of the rheostatand controllingswitch. Fig. 2 is a central section through the same.Fig. 3 is a rear View of the guard, and Fig. 4 is a diagram indicatingthe connection of the resistance-conduetor.

It is common, though not universal, to surround ventilating-fans withguards to prevent injury to the fan-blades and to direct the airforward. \Ve have shown such a guard in the accompanying drawings. Itconsists of two metal rings 1 2, having a diameter slightly larger thanthe diameter of the fan and perforated at intervals for the reception ofthe cross rods or wires 3, which extend from the rear ring 1, throughthe front ring 2, to a central front ring 4:. Some of the rods or wiresare extended beyond the rear ring 1 and are bent to form loops 5, thefree end of the wire being twisted around the body of the wire, asindicated at 6. The loops 5 provide means by which the guard may besecured to a suit able support. Between the rings 1 2 is a band 7, whichmay be of metal or of insulating material, and which rests directly uponthe cross rods or wires 3. Evidentlyit is not essential that this bandshould be continuous or imperforate, or indeed that it should be used atall, since the resistance-00nd uctor hereinafter described may be wounddirectly on the circle of rods or wires On the outside of the band wewind a resistance-00nductor S. This The terminals of the wire areconnected by wires 9 10 to the two terminal pins 11 12 of the switch.From the center of the resistancewire a connection is made by means ofwire 13 to the terminal 1i of the switch. The wires 9 1O 13 are suitablyinsnlated and are led along the rods or wires 3, being preferably boundto said wires, as indicated at 15.

The switch device placed at the center of the guard and supported by thering 4 consists of a hard-rubber base or other insulating material 16,at the center of which is a spindle 17, carrying a handle 18, on whichis a switch-arm l9. Near the outer edge of the base are metal pins 1112, &c., to which the circuit-wires may be connected by means ofbinding-screws 20. This switch is put in place from the rear of theguard, the main body of the base passing through the ring until thelower flange of the base rests against the ring. Screws 21 (see Fig. 1)are then passed through the ring into the base, securing it in place. InFig. 4 is indicated an electric motor having a field-magnet coil 22 andan armature 23, to the shaft of which is secured a fan 24, around whichis the guard. The switch which belongs within ring 4: (shown in sectionin Fi 4c) and the resistance-conductor are shown detached from the guardin the diagram for convenience of illustration. The terminal 11 isconnected to one end of the conductor 8. The opposite end is connectedto terminal 12, whiehis connected to the field-magnet coil, and thencethrough the armature to the generator 25, the opposite pole of which isconnected by wire 26 to a switch-arm 19. hen the arm is moved from theposition in which it is shown onto contact 11, the circuit through themotor is closed, and all of the resistance 8 is in circuit, and themotor will run slowly. If the switch-arm is moved to contact 14:,onehalf of the resistance will be thrown out of circuit and the motorwill run faster, and

resistance-wire wound around said guard guard, has a large part of itssurface exposed to the air, and the operation of the fan tends to keepthe conductor cool.

What we claim is l. The combination of a fan-guard and aresistance-conductor mounted directly thereon, substantially asdescribed.

2. The combination of a fan-guard and a 7 substantially as described.-

3. The combination of an electric motor, a fan driven thereby,afan-guard, and a resistance-conductor on said guard for regulating theelectric motor, substantially as described.

4. The combination of an electric motor, a fan driven thereby, afan-guard, a resistanceconductor thereon, and a switch for throwing moreor less of the resistance into the motorcircuit to regulate its speed,substantially as described.

5. The combination of a fan-guard, a resistance thereon, and aswitch atthe center of the guard and connected to the resistance-eonduetor,substantially as described.

(3. The combination, in a fan-guard, of the front and rear rings, thewires connecting the same, the band between said rings, and theresistance-conductor on said bands, substantially as described.

7. The combination of a fan-guard, a conductor on said guard, a switchat the center of the guard, and conductors extending from said switch tothe conductor 011 the guard, substantially as described.

8. The combination, with a fan-guard having a central ring 4, of aswitch supported in said ring, substantially as described.

9. The combination of an electric motor, a fan driven thereby, a guardfor the fan, and a switch at the center of the guard for controlling themotor, substantially as described.

This specification signed and witnessed this 21st day of August, 1891.

WILLIAM S. ANDREWS.

' ALDRED K. WARREN.

Witnesses:

HENRY PRICE BALL, HENRY E. J oiiL.

